The increase in disorder which leads to a metal-insulator transition through increasing electron localization also leads to a gradual destruction of superconductivity. Their measurements in granular aluminum have demonstrated the close relation of the two phenomena and the existence of a metallic non-superconducting phase. They will make similar measurements on other materials, including granular composites, doped strontium titanate, and high temperature superconducting metal oxides, where their initial work shows similar behavior. They will investigate superconductivity in the vicinity of the metal-insulator transition and the influence of increasing electron localization on its disappearance by a wide range of electric, magnetic and thermal measurements. The specimens will include single crystal and polycrystalline bulk material as well as thin films, prepared partly in their laboratory and also in several collaborating universities, governmental and industrial laboratories.
